This invention relates to an arrow head commonly referred to as a broadhead. In particular, the invention relates to expanding, exposed-blade arrow heads.
Currently, there are two common types of broadheads on the market: fixed blade and mechanical. Both have their advantages and disadvantages.
Fixed blades have the cutting blades exposed and mounted so they maintain their position when passing through the target. This type of broadhead usually has a cutting diameter in the range from 0.875 to 1.500 inches. This cutting diameter is fixed, and does not change during flight. Most states have regulations that place a limit on the smallest cutting diameter a broadhead can have. These regulations commonly stipulate a minimum cutting diameter of 0.875 inch.
Mechanical broadheads have cutting blades that are initially folded in or retracted. Upon impact with the target, the blades expand to a given cutting diameter. Most mechanical broadheads open in a rotational fashion. They usually have a tab or protrusion on the leading edge of the arrow head that catches the flesh of the target which folds the blade open, rotating the blade around a fixed pivot point near the following portion of the broadhead. This action consumes vital kinetic energy, forcing the blades in a counter productive direction until the blades rotate over center. Also, the blades are supported (connected to the central portion of the arrow head) at only one point, the pivot point, rendering them easily bent.
Mechanical broadheads usually have a cutting diameter after full expansion that ranges from one inch to three inches. The hunting regulations of some states prohibit the use of mechanical broadheads because they may not open correctly and ensure a humane kill.
Each of the aforementioned broadhead types typically has a leading tip consisting of mild steel, or an inset piece of razor blade. These two types of tip usually work well when they hit flesh. When they hit a heavy bone, however, they bend, fold, or dull.
Common problems associated with these two types of background art broadheads have consumer sentiment split about which type works best. Fixed blade arrow heads are favored for the security of having the cutting blades exposed and fixed in position. Conversely, fixed blades are usually considered less accurate because the exposed blades are influenced by the air as it passes through them, causing the arrow to hit a different spot than the archer's field point. This requires that archers sight in differently with fixed broadheads.
Mechanical broadheads have a lower aerodynamic co-efficient, making the influence of air pressure during flight less. This allows a mechanical broadhead to hit the same desired location as the archer's field point. Moreover, the probability that a mechanical broadhead will not open at all or will not open to full cutting diameter is low. A significant proportion of consumers prefer the larger cutting diameter of mechanical broadheads. One of the problems with these large-cutting-diameter mechanical broadheads is that the action of the blades folding open consumes a large percentage of the initial energy of the arrow. This may rob enough kinetic energy from the arrow to prevent a humane kill. Another limitation is the need to hold the blades in the retracted position with a band, e.g., a rubber band, that must be replaced between uses.
The background art is characterized by U.S. Pat. Nos. 5,090,709; 5,100,143; 5,112,063; 5,172,916; 6,200,237; 6,270,435; 6,290,903; 6,322,464; 6,517,454; 6,595,881; 6,626,776; 6,669,586; 6,910,979; 6,935,976 and 7,226,375; the disclosures of which patents are incorporated by reference as if fully set forth herein.
None of the background art references disclose a mechanical broadhead that supports the forward end of each of its blades pivotably and the body of each of its blades laterally, thereby providing two points of support for each blade. Moreover, none of the background art references disclose a mechanical broadhead that comprises a plunger to which each of its blades is pivotably attached that is longitudinally movable relative to a ferrule having blade holders to which each of its blades is slidably attached, thereby securing said plunger to said ferrule. Also, none of the background art references disclose a mechanical broadhead that relies on a longitudinally compressible or expandable spring or a shearable or crushable structure to maintain its blades in a retracted position during flight.